A test and pressure relief valve should be installed to assure relief of internal pressure prior to servicing and as a visual indication of trap operation.
应该安装一个测试和压力安全阀，确保内部压力能够在维修前得到释放，并作为疏水阀工作的直观显示。
2
Purpose: To testoperation of pressure differential relief valve.
目的：检测差压安全阀的工作性能。
3
The specifications for seat sealing test, body sealing test, body strength test, valve long term test, fatigue strength test and operation torque of plastic valves were summarized.